pythonmatrixgraph-theory

Adjacency matrix with string nodes in Python


I have a csv file of nodes and a csv file of edges - all the nodes are STRING. I need help please for how can I build an adjacency matrix of this graph in python?

Example of the data:

Nodes csv:
a
b
c
d

Edges csv:
a,b
b,c
a,c
d,a
b,d

I want it to be presented as an adjacency matrix:
  a  b  c  d
a 0  1  1  1
b 1  0  1  1
c 1  1  0  0
d 1  1  0  0

Thank you!


Solution

  • Ok: assuming your nodes and edges have been converted to lists as follows, this works (as you can see, the code is self-explanatory):

    nodes = ['a','b','c','d']
    edges = [('a','b'),('b','c'),('a','c'),('d','a'),('b','d')]
    
    import numpy as np
    n = len(nodes)
    matrix = np.zeros((n,n), dtype=int)
    for i in range(n):
        for j in range(n):
            if (nodes[i],nodes[j]) in edges or (nodes[j],nodes[i]) in edges:
                matrix[i,j] = matrix[j,i] = 1